Light-emitting device and lighting device provided with the same

ABSTRACT

A light-emitting device capable of ensuring an electric connection between a light-emitting element and an electrode without generating any problem in practical use, by both connecting methods with a solder and a connector, and a lighting device provided with the light-emitting device are provided. The light-emitting device according to the present invention has a plurality of LED chips, and a soldering electrode land and a connector connecting electrode land electrically connected to the chips, on a ceramic substrate. The soldering electrode land is formed of a first conductive material having a function to prevent diffusion to a solder, and the connector connecting electrode land is formed of a second conductive material having a function to prevent oxidation.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.13/242,329 filed Sep. 23, 2011, pending, which is a non-provisionalapplication which claims priority under 35 U.S.C. §119(a) on PatentApplication No. 2010-222440 filed in Japan on Sep. 30, 2010, the entirecontents of each of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a light-emitting device and a lightingdevice provided with the same.

2. Description of the Related Art

Conventionally, a light-emitting device is provided with alight-emitting element (refer to Japanese Patent Laying-Open No.2007-116095 (hereinafter, referred to as the patent document 1)).

FIG. 12 is a schematic structure diagram of a light-emitting devicedisclosed in the patent document 1. A light-emitting device 100 includesa LED chip 101, and the LED chip 101 is mounted on a wiring substrate103. The wiring substrate 103 serves as a base member of the LED chip101.

An electrode provided on one surface side of the LED chip 101 isconnected to a bonding wire 105, and the bonding wire 105 extends in adirection along one diagonal line of the LED chip 101.

References 107 and 109 each represent a conductor pattern, and each ofthem is composed of a laminated film having a Cu film, a Ni film, and anAu film. In a planar view, a part on the inner side of a frame(reflector (not shown)) serves as the inner lead 107, and a part on theouter side of the frame serves as the outer lead 109.

As disclosed in the patent document 1, in a case where the conductorpattern to be externally connected is formed of gold (Au film) on thesubstrate 103, and a solder is used to externally connect the conductorpattern, the gold contained in the conductor pattern is diffused in thesolder and an intermetallic compound is formed in some cases. Thus, whenthis phenomenon is repeatedly generated, the Au film, the Cu film, andthe Ni film disappear, and an electrode land and the solder are notconnected, which is inconvenient in practical use.

In addition, a user who wants to make an external connection with aconnector other than the solder cannot use the light-emitting devicedisclosed in the patent document 1. Meanwhile, a user who wants to makethe external connection with the solder suffers from the above problem.

SUMMARY OF THE INVENTION

The present invention was made in view of the above problem, and it isan object of the present invention to provide a light-emitting devicecapable of ensuring an electric connection between a light-emittingelement and an electrode by both connecting methods with a solder and aconnector without generating any problem in practical use, and alighting device provided with the light-emitting device.

In addition, it is an object of the present invention to provide alight-emitting device capable of densely and compactly mounting LEDchips.

In order to attain the above object, a light-emitting device accordingto the present invention is characterized by including a light-emittingpart, and a soldering electrode land and a connector connectingelectrode land each electrically connected to the light-emitting part,on a substrate, in which the soldering electrode land is formed of afirst conductive material having a function to prevent diffusion to asolder, and the connector connecting electrode land is formed of asecond conductive material having a function to prevent oxidation.

At this time, it is preferable that the soldering electrode land has anuppermost surface made of the first conductive material, and theconnector connecting electrode land has an uppermost surface made of thesecond conductive material.

Here, the first conductive material includes any one of Ag, Ag—Pt andAg—Pd.

In addition, the second conductive material includes Au.

Furthermore, the light-emitting device is further characterized in thatthe soldering electrode land includes a pair of a first solderingelectrode land connected to an anode, and a second soldering electrodeland connected to a cathode, and the connector connecting electrode landincludes a pair of a first connector connecting electrode land connectedto the anode and a second connector connecting electrode land connectedto the cathode.

At this time, it is preferably that the substrate has a rectangularshape, and either or both of the pair of the first soldering electrodeland and the second soldering electrode land, and the pair of the firstconnector connecting electrode land and the second connector connectingelectrode land are arranged at corners of the substrate.

In addition, the light-emitting device is characterized in that a firstwiring pattern connected to the anode, and a second wiring patternconnected to the cathode are arranged so as to be opposed to each otheron the substrate, and the light-emitting part is electrically connectedto the first soldering electrode land and the first connector connectingelectrode land through the first wiring pattern, and electricallyconnected to the second soldering electrode land and the secondconnector connecting electrode land through the second wiring pattern.

At this time, the first wiring pattern and the second wiring patternhave respective arc shapes each constituting a part of the same circularring, and the light-emitting part is covered with a sealing body filledin the circular ring.

In addition to the above characteristics, the light-emitting device ischaracterized by including a printing resistive element having one endconnected to one end of the first wiring pattern, and having the otherend connected to one end of the second wiring pattern, in which theprinting resistive element has an arc shape constituting a part of thecircular ring.

According to the shape of the above light-emitting device, thelight-emitting device can show rotation symmetry with the LED chipsarranged in the inner side of the circular ring. At this time, theseries circuits each composed of the LED chips connected in series arearranged as parallel lines, so that the light-emitting device canimplement high luminance of 25 W or more.

According to the shape of the above light-emitting device, thelight-emitting device can show rotation symmetry with the LED chipsarranged in the inner side of the circular ring. At this time, theseries circuits each composed of the LED chips connected in series arearranged as parallel lines, so that the light-emitting device canimplement high luminance of 25 W or more.

In addition, a lighting device is characterized by including thelight-emitting device having the above characteristics, and a connectorjig, in which the connector jig includes a resin plate having alight-emitting surface opening, and a connector terminal opening to bepenetrated by a connector terminal, and the light-emitting device andthe connector jig are overlapped in such a manner that thelight-emitting part is exposed in the light-emitting surface opening,and the connector connecting electrode land and the connector terminalopening are opposed to each other.

In addition to the above characteristics, the lighting device is furthercharacterized in that an outer periphery of the connector jig does notprotrude from an outer periphery of the light-emitting device whenviewed from a direction perpendicular to an overlapped surface of thelight-emitting device and the connector jig.

According to the light-emitting device of the present invention, sincethe soldering electrode land and the connector connecting electrode landare both previously provided on the substrate, either one of theconnection with the solder and the connector can be employed accordingto a usage way of the user when the user tries to ensure the externalelectric connection. Thus, a versatile light-emitting device can beprovided.

In addition, in the case of the external connection with the solder, thepresent invention solves the problem that Au is diffused in the solderand the intermetallic compound is formed, so that electric connectioncannot be ensured like the conventional case because the solderingelectrode land is formed of the first conductive material having thefunction to prevent diffusion to the solder.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are schematic structure diagrams showing one example ofa light-emitting device according to the present invention;

FIGS. 2A and 2B are schematic structure diagrams showing a stage beforethe light-emitting device according to the present invention iscompleted;

FIGS. 3A and 3B are schematic structure diagrams showing a connectorjig, and a state in which the connector jig and the light-emittingdevice are overlapped, respectively.

FIG. 4 is a schematic structure diagram showing a state fixed to a caseunder the condition that the connector jig and the light-emitting deviceare overlapped;

FIG. 5 is an outline view of a lighting device mounting thelight-emitting device;

FIGS. 6A and 6B are views to explain a method for ensuring electricconnection between a connector connecting electrode land and theconnector jig;

FIG. 7 is a schematic structure diagram showing a state in which thelight-emitting device externally connected with a solder is fixed to thecase;

FIGS. 8A and 8B are schematic structure diagrams showing another exampleof the light-emitting device according to the present invention;

FIGS. 9A and 9B are schematic structure diagrams showing another exampleof the light-emitting device according to the present invention;

FIGS. 10A and 10B are schematic structure diagrams showing a state inwhich the connector jig and the light-emitting device are overlapped;

FIGS. 11A and 11B are schematic structure diagrams showing another statein which the connector jig and the light-emitting device are overlapped;and

FIG. 12 is a schematic structure diagram of a conventional lightingdevice.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1A and 1B are schematic structure diagrams showing one example ofa light-emitting device of this embodiment. As shown in FIGS. 1A and 1B,a light-emitting device 1 according to this embodiment includes aceramic substrate 3, wiring patterns 7 (7 a and 7 k), a phosphorcontaining resin layer 9, LED chips 11, a wire 13, a printing resistiveelement 15, soldering electrode lands 17 (17 a and 17 k), connectorconnecting electrode lands 19 (19 a and 19 k), a resin dam 21, andpositioning openings 25. In addition, FIG. 1A is a top view and FIG. 1Bis a cross-sectional view. In FIG. 1A, an inner side is transparentlyshown in order to make a connection relationship clear.

In addition, FIGS. 2A and 2B are schematic views showing a state priorto the state shown in FIG. 1A. FIG. 2A is a view showing a schematicstructure before the LED chips 11 are mounted and FIG. 2B is a viewshowing a schematic structure after the LED chips 11 are mounted andbefore the phosphor containing resin layer 9 and the resin dam 21 areformed.

The wiring pattern 7 a, and the electrode lands 17 a and 19 a are allelectrically connected to an anode terminal, and the wiring pattern 7 k,and the electrode lands 17 k and 19 k are all electrically connected toa cathode terminal.

The ceramic substrate 3 is formed into a rectangular shape. For example,its outline is 24 mm×20 mm, and its thickness is 1 mm.

Thus, the electrode lands 17 a and 19 a connected to the anode, and theelectrode lands 17 k and 19 k connected to the cathode are arranged atdiagonally opposed corner parts of the ceramic substrate 3,respectively.

The soldering electrode lands 17 a and 17 k are used when an externalconnection (for the purpose of power supply) with the wiring pattern 7is made with a solder. Each of them is formed of Ag—Pt by a screenprinting method. An example of its thickness is 20 μm.

The Ag—Pt layer is preferably formed on an uppermost layer of each ofthe soldering electrode lands 17 a and 17 k, but another metal layer maybe thinly formed on the surface of the Ag—Pt layer because it is onlynecessary to prevent a diffusion reaction to the solder in the Ag—Ptlayer. In addition, a metal layer having small specific resistance maybe formed under the Ag—Pt layer.

The connector connecting electrode lands 19 a and 19 k are used when anexternal connection (for the purpose of power supply) with the wiringpattern 7 is made with a connector. Each of them is formed of Au by ascreen printing method. An example of its thickness is 3 μm.

Here, the material Au used for the connector connecting electrode lands19 a and 19 k has a feature that prevents an oxide film from beingformed on a surface. Thus, the external electric connection can beeasily ensured through a connector contact.

In addition, the Au layer is preferably formed on an uppermost surfaceof each of the connector connecting electrode lands 19 a and 19 k to beeasily connected at the time of the connector contact, but a hard metallayer (such as Ti or W) having small specific resistance may be thinlyformed to prevent a damage at the time of the connector contact. Inaddition, instead of the Au layer, a hard metal which is hardly oxidizedand has small specific resistance may be used.

The wiring patterns 7 a and 7 k are formed on the ceramic substrate 3 soas to be opposed to each other. Each of them has an arc shape which ispartially cut out from a circular ring when viewed from the top of thelight-emitting device 1. In addition, the soldering electrode land 17 ais connected to one end of the wiring pattern 7 a through a leadingline, and the soldering electrode land 17 k is connected to one end ofthe wiring pattern 7 k through a leading line. The connector connectingelectrode land 19 a is electrically connected to the soldering electrodeland 17 a through a leading line or a contact electrode, and theconnector connecting electrode land 19 k is also electrically connectedto the soldering electrode land 17 k in a similar way.

The printing resistive element 15 is provided in order to enhance anelectrostatic withstand voltage, and composed of RhO₂ having aresistance value of 50Ω, in which its width is 200 μm and its width is 6μm. As shown in FIGS. 1A to 2B, the printing resistive element 15 isarranged so as to connect one end of the wiring pattern 7 a and one endof the wiring pattern 7 k, and has an arc shape partially cut out from acircular ring. According to this embodiment, each of the wiring pattern7 a, the printing resistive element 15, and the wiring pattern 7 kconstitutes a part of an outer periphery of the same circular ring.

The plurality of LED chips 11 are mounted on the ceramic substrate 3.According to this embodiment, 12 series circuits each composed of 12 LEDchips 11 are arranged as parallel lines.

In addition, the LED chips 11 are linearly arranged so as to be roughlyparallel to one side of the substrate. Thus, the number of the chips inthe line is greatest in the vicinity of the center of the circular ringshape composed of the wiring patterns 7 and the printing resistiveelement 15, and the number of the chips is reduced toward the peripheryof the substrate from the center, so that the LED chips can be denselyarranged in an area surrounded by the wiring patterns 7.

When the LED chips 11 are arranged as described above, the outline ofthe arranged LED chips 11 becomes the same (or similar) shape as theoutline of the phosphor containing resin layer 9 (sealing body) whenviewed from the top of the light-emitting device 1. According to thisembodiment, as shown in FIGS. 1A and 1B, the shape of the sealing bodyhas a circular shape when viewed from the top, and the outline of thearranged LED chips 11 also has a circular shape. This configuration cansolve the problem that a light-emitting pattern cannot have the sameshape as that of the sealing body due to a shadow caused because a lightsource is not arranged in the vicinity of the sealing body.

Basically, the adjacent LED chips 11 are directly connected by the wire13 in the one LED chip line. However, in the vicinity of the peripheryof the substrate in which the number of the chips in the same line issmaller, the LED chip is electrically connected to the LED chip in theadjacent line so that the number of the LED chips 11 is to be the samein each series circuit. The LED chip 11 arranged in the vicinity of thewiring pattern 7 is directly and electrically connected to the wiringpattern 7 through the wire.

The resin dam 21 is provided to dam the sealed resin and composed of acolored material (preferably white or milky white). According to thisembodiment, the resin dam 21 is composed of a white silicon resin(containing TiO₂ as a filler) and formed into a circular ring shapehaving a width of 1 mm and a diameter of 9 mm. It is formed such thatafter the resin is applied, it is subjected to a curing treatment at150° C. for 60 minutes. As shown in FIG. 1A, the resin dam 21 ispreferably formed so as to cover the wiring patterns 7, the printingresistive element 15, and a part of the wire 13.

The phosphor containing resin layer 9 is formed to convert the light(such as blue light) emitted from the LED chip to white light. Accordingto this embodiment, a material containing a green phosphor (such asCa₃(Sr—Mg)₂Si₃O₁₂:Ce) and a red phosphor (such as (Sr—Ca)AlSiN₃:Eu) isinjected into the inner side of the resin dam 21 formed into the ringshape, and thermally cured at 150° C. for 5 hours, whereby the phosphorcontaining resin layer 9 is formed.

According to this embodiment, as shown in FIG. 1A, the two positioningopenings 25 are formed at the diagonally opposed corners of the ceramicsubstrate 3. This opening 25 is used when a connector jig which will bedescribed below is screwed on the light-emitting device 1.

FIGS. 3A and 3B are schematic structure diagrams showing the connectorjig, and a state after the connector jig and the light-emitting device 1are overlapped. FIG. 3A shows the connector jig, and FIG. 3B shows thestate after the connector jig and the light-emitting device 1 areoverlapped.

A connector jig 31 is provided to electrically connect the connectorconnecting electrode lands 19 (19 a and 19 k) formed on the ceramicsubstrate 3 to an external line, and composed of a resin plate 30 havingalmost the same size as that of the ceramic substrate 3. A positioningopening 33, a connector terminal opening 35, and a light-emittingsurface opening 39 are formed in the resin plate 30. A slanted part 37is formed on an outer peripheral side surface of the light-emittingsurface opening 39 and serves as a reflection member. The resin plate 30is made of a resin such as PBT (polybutylene terephthalate) resin or aPC (polycarbonate) resin. According to this embodiment, the resin plate30 is composed of a milky white or white PBT resin having a highreflection rate with respect to light emitted from the light-emittingpart.

As shown in FIG. 3A, the positioning openings 33 are provided at one oftwo pairs of diagonally opposed corners of the connector jig 31, and theconnector terminal openings 35 are provided at the other of the twopairs of diagonally opposed corners thereof. The connector terminalopening 35 is configured so that the connector can be inserted from aside surface to the inner side of the resin plate 30.

As shown in FIG. 3B, after the light-emitting device 1 and the connectorjig 31 are overlapped, the opening 25 provided in the ceramic substrate3 of the light-emitting device 1 is overlapped with the positioningopening 33 provided in the connector jig 31. In addition, thelight-emitting surface containing the LED chips 11 and the phosphorcontaining resin layer 9 is exposed in the light-emitting surfaceopening 39. In addition, each of the connector connecting electrodelands 19 a and 19 k provided in the light-emitting device 1 is partiallyopposed to the connector terminal opening 35 provided in the connectorjig 31 in a vertical direction. In FIG. 3B, in order to clearlyunderstand that the connector connecting electrode lands 19 a and 19 kexist under the connector terminal opening 35, the resin plate 30positioned just above them is transparently shown.

Thus, the connector jig 31 is set and a connector 46 is fit in theconnector terminal opening 35, whereby, as shown in FIG. 4, a lead (leadin the connector) 41 attached to the connector is electrically connectedto the connector connecting electrode lands 19 a and 19 k. Thus, a screw43 (such as M5 screw) is fit in so as to penetrate the openings 25 and33 and fixed to a case 51. Then, a lens dome 55 is fit in, whereby a LEDlighting device 50 is completed (refer to FIG. 5). In addition, in FIG.5, reference 53 represents a cap and may be integrally provided with thecase 51.

FIG. 6 is a conceptual view to explain a method to ensure the electricconnection between the connector connecting electrode land 19 and theconnector jig 31 when the resin plate 30 of the connector jig 31 and theceramic substrate 3 of the light-emitting device 1 are to be overlapped.In FIG. 6, reference 45 represents a lead attached to the jig.

As described above, when the light-emitting device 1 and the connectorjig 31 are overlapped such that the opening 25 provided in the ceramicsubstrate 3 and the positioning opening 33 provided in the resin plate30 are overlapped, the connector terminal opening 35 provided in theconnector jig 31 is opposed to the connector connecting electrode land19 in the vertical direction. The lead 45 attached to the jig isprovided in the connector jig 31 to electrically connect the lead 41 inthe connector to the connector connecting electrode land 19.

The lead 45 attached to the jig is formed of a conductive material woundinto the form of a spring. The spring shape is provided to increase acontact area between the lead 45 and the connector connecting electrodeland 19 to disperse force applied at the time of contact to prevent anedge of the lead 45 attached to the jig from sharply coming in contactwith the surface of the connector connecting electrode land 19 anddamaging the surface after the connector jig 31 and the light-emittingdevice 1 are overlapped. As described above, when fixed to the case 51,the screw 43 is fit in the opening 25 and 33 so as to penetrate them, sothat the lead 45 and the connector connecting electrode land 19 aresurely connected electrically.

In addition, as shown in FIG. 6B, it is preferable that a click 48 ispreviously formed in the connector terminal opening 35 to prevent theconnector 46 inserted in the connector terminal opening 35 fromescaping.

In addition, when the light-emitting device 1 of this embodiment isexternally connected with soldering, as shown in FIG. 7, the solderingelectrode land 17 (17 a and 17 k) is soldered, whereby an external lead42 can be electrically connected to the soldering electrode land 17through a solder 47. Thus, the ceramic substrate 3 is fixed to the case51 by a press part 49. According to the light-emitting device 1 of thisembodiment, although both of the soldering electrode land 17 and theconnector connecting electrode land 19 are provided, since each of themis arranged in the vicinity of the corner of the ceramic substrate 3, aspace for providing the press part 49 can be sufficiently provided inthe periphery of the substrate 3.

Thus, the whole is fixed by a screw 44 with the ceramic substrate 3 andthe case 51 fixed to each other by the press part 49. After that,similar to the case of the connector connection, the lens dome 55 is fitin, whereby the LED lighting device 50 is formed (refer to FIG. 5).

According to the configuration of this embodiment, since each of thesoldering electrode land 17 (17 a and 17 k) and the connector connectingelectrode land 19 (19 a and 19 k) is previously provided on the ceramicsubstrate 3, either one of the methods of soldering and connectorconnecting can be employed according to a usage mode of a user when thewiring pattern 7 is electrically connected to the outside. In addition,in the case where the external connection is provided with soldering,the conventional problem that Au is diffused in the solder and forms anintermetallic compound so that the electric connection cannot to beensured is not caused because the soldering electrode land 17 is notformed of Au.

In addition, the LED chips can be densely arranged in the light-emittingdevice having the circular shape viewed from the top, which contributesto miniaturization of the lighting device having high luminance of 25 W.

Furthermore, in the case where the light-emitting device 1 according tothis embodiment is externally connected through the connector, theconnector jig having almost the same size as that of the ceramicsubstrate 3 having the LED chips 11 is overlapped. At this time, sincethe connector jig 31 has the openings (33, 35, and 39) corresponding tothe structure of the ceramic substrate 3, positioning is automaticallymade when it is overlapped. Thus, the light-emitting part (LED chips 11)of the light-emitting device 1 can be positioned. In addition, since theconnector jig 31 is composed of the resin plate 30, the ceramicsubstrate 3 having the LED chips 11 can be protected.

[Variation]

The arrangement positions of the soldering electrode land 17 and theconnector connecting electrode land 19 are not limited to those shown inFIG. 1A. Hereinafter, a variation will be described with reference toFIGS. 8A to 9B.

According to a variation shown in FIG. 8A, the light-emitting device 1is provided such that the wiring pattern 7 a is electrically connectedto the connector connecting electrode land 19 a through a leading lineconnected to a region around the center of the wiring pattern 7 a, andthe wiring pattern 7 a is electrically connected to the solderingelectrode land 17 a through a leading line extending from the connectorconnecting electrode land 19 a. This is applied to the connectorconnecting electrode land 19 k and the soldering electrode land 17 k.

When the wiring pattern 7 is externally connected through the connectorterminal, in the light-emitting device 1 shown in FIG. 8A, the connectorjig 31 shown in FIG. 8B is overlapped with the ceramic substrate 3. Theconnector jig 31 shown in FIG. 8B is provided such that the connectorterminal openings 35 are arranged almost in the center of opposed onepair of sides, in a peripheral part of the resin plate 30, and theconnector jig 31 is overlapped with the ceramic substrate 3, wherebyeach of the connector connecting electrode lands 19 (19 a and 19 k) ispartially exposed in each of the connector terminal openings 35. Thepositioning opening 33 and the light-emitting surface opening 39 areformed similarly to the above embodiment.

Thus, the external connection can be made through the connector by thesame method as shown in FIG. 4, and the external connection can be madethrough the solder by the same method as shown in FIG. 7.

In addition, according to a variation shown in FIG. 9A, thelight-emitting device 1 is provided such that the connector connectingelectrode lands 19 a and 19 k are arranged at one diagonally opposedpair of corners of the ceramic substrate 3, and the soldering electrodelands 17 a and 17 k are arranged at the other diagonally opposed pair ofcorners of the ceramic substrate 3. That is, the connector connectingelectrode lands 19 a and 19 k, and the soldering electrode lands 17 aand 17 k are formed at the four corners of the ceramic substrate 3,respectively. In addition, the opening 25 is provided almost in thecenter of the opposed one pair of sides, in a peripheral part of theceramic substrate 3.

Thus, the connector connecting electrode land 19 a is electricallyconnected to one terminal of the wiring pattern 7 a through a leadingline, and the soldering electrode land 17 a is electrically connected tothe other terminal of the wiring pattern 7 a through a leading line.Similarly, the connector connecting electrode land 19 k is electricallyconnected to one terminal of the wiring pattern 7 k through a leadingline, and the soldering electrode land 17 k is electrically connected tothe other terminal of the wiring pattern 7 k through an leading line.

When the wiring pattern 7 is externally connected through a connectorterminal, in the light-emitting device 1 shown in FIG. 9A, the connectorjig 31 shown in FIG. 9B is overlapped with the ceramic substrate 3. Theconnector jig 31 shown in FIG. 9B is provided such that the connectorpositioning openings 33 are arranged almost in the center of opposed onepair of sides, in a peripheral part of the resin plate 30, and theconnector jig 31 is overlapped with the ceramic substrate 3, whereby thepositioning openings 33 are overlapped with the openings 25,respectively. In addition, the connector terminal openings 35 areprovided at one diagonally opposed pair of corners, and when theconnector jig 31 is overlapped with the ceramic substrate 3, theconnector connecting electrode land 19 is partially exposed in theconnector terminal opening 35.

Thus, the external connection can be made through the connector by thesame method as shown in FIG. 4, and the external connection can be madethrough the solder by the same method as shown in FIG. 7.

FIGS. 10A and 10B are additional schematic structure diagrams showingthe state in which the connector jig 31 and the light-emitting device 1are overlapped, in the configuration shown in FIGS. 9A and 9B. FIG. 10Ais a view showing a state when viewed from the top without a part of thelight-emitting device being transparently shown, and FIG. 10B is a viewshowing a cross-sectional state cut by a line connecting the two opposedopenings 25 (33). As described above, the LED chips 11 are formed underthe resin layer 9, and the lead 45 attached to the jig and the connectorconnecting electrode land 19 are formed under the connector connectingopening 35 although not shown in the drawing.

FIGS. 11A and 11B are additional schematic structure diagrams showingthe state in which the connector jig 31 and the light-emitting device 1are overlapped, in the configurations shown in FIGS. 1A and 1B, andFIGS. 8A and 8B, respectively when viewed from the top without a part ofthe light-emitting device being transparently shown, similar to FIG.10A. FIGS. 10A and 10B, and FIGS. 11A and 11B are provided to understandthe structure.

[Other Embodiments]

Hereinafter, other embodiments will be described.

(1) While the ceramic substrate is used as the substrate 3 in the aboveembodiment, the substrate may be a metal core substrate provided suchthat an insulation layer is formed on a surface of a metal substrateserving as a core.

(2) While the soldering electrode land 17 is made of Ag—Pt in the aboveembodiment, it only has to contain a conductive material (correspondingto a first conductive material) having a function to prevent diffusionto the solder. Thus, the material may include Ag or Ag—Pd other than theAg—Pt. In addition, at this time, it is preferable that an uppermostsurface part which is in contact with at least the solder is made of thefirst conductive material.

In addition, while the connector connecting electrode land 19 is made ofAu in the above embodiment, it only has to contain a conductive material(corresponding to a second conductive material) having a function toprevent oxidation from proceeding. The material Au is used as oneexample of the conductive material to prevent the oxidation fromproceeding. In addition, at this time, it is preferable that anuppermost surface which is in contact with the lead (the lead 45attached to the jig in the structure shown in FIG. 6) electricallyconnected to at least the connector is made of the second conductivematerial.

(3) While the adjacent LED chips 11 are directly and electricallyconnected by the wire 13 in the above embodiment, they may be connectedthrough a relay electrode.

(4) While the soldering electrode land 17 is provided on the same side(main surface side) as the connector connecting electrode land 19, onthe ceramic substrate 3 in the above embodiment, it may be provided on aback surface side of the substrate 3. In this case, a penetrationelectrode which penetrates the substrate to be connected to the wiringpattern 7 is provided, so that the soldering electrode land 17 providedon the back surface side is electrically connected to the penetrationelectrode.

In addition, the soldering electrode land 17 may be provided on a sidesurface of the substrate 3.

(5) The shapes of the electrode lands (17 and 19) and the openings (25,33, and 35) are only shown as one example, and other shapes may beemployed.

(6) While the resin plate 30 constituting the connector jig 31 hasalmost the same size as that of the ceramic substrate 3 having the LEDchips 11 in the above embodiment, the resin plate 30 may have any size.However, with a view to miniaturizing the lighting device 50, the resinplate 30 is preferably miniaturized within a range in which the openings(25 and 33) of the resin plate 30 and the ceramic substrate 3 can beoverlapped. That is, it is preferable that the outer periphery of theconnector jig 31 does not protrude from the outer periphery of thelight-emitting device 1 when viewed from a direction perpendicular tothe overlapped surface of the light-emitting device and the connectorjig.

(7) While one or both of the soldering electrode land 17 and theconnector connecting electrode land 19 are arranged at the corners ofthe ceramic substrate 3 in the above embodiment, the arrangementposition is not limited to the corner. However, the case where theelectrode land is arranged at the corner of the ceramic substrate 3 ispreferable because a space for the opening 25 can be sufficientlyensured in the ceramic substrate 3, and a ratio of the light emittedfrom the LED chip 11 absorbed by the electrode lands (17 and 19) can bereduced.

(8) While the connector jig 31 is composed of the white or milky whiteresin plate 30 in the above embodiment, the connector jig 31 may becomposed of a transparent member in a case where it is used only forfixing the ceramic substrate 3 to ensure the connector connectionwithout having a function as a reflection member.

(9) While the light-emitting device 1 has the printing resistive element15 in the above embodiment, the printing resistive element is notnecessarily provided when the withstand voltage protecting function isnot executed. In addition, as an element having the withstand voltageprotecting function, a zener diode may be mounted instead of theprinting resistive element.

(10) While the 12 series circuits each composed of 12 LED chips 11connected in series are arranged as parallel lines on the substrate 3 inthe above embodiment, as a matter of course, the number of the LED chips11 connected in series, and the number of the series circuits (parallelline number) are not limited to the above numbers. In addition, thenumber of chips connected in series is not necessarily equal to thenumber of the parallel series circuits.

In addition, in FIG. 1A, the LED chips 11 of the adjacent lines areappropriately connected in series in the vicinity of the peripheral partof the substrate in which the number of the chips belonging to the sameline is smaller, so that the number of the LED chips 11 constituting theseries circuit can be equalized. At this time, the LED chips 11 in thethree or more adjacent lines may be incorporated as the components ofthe series circuit.

In addition, in FIG. 1A, the LED chips 11 of the adjacent lines areappropriately connected in series in the vicinity of the peripheral partof the substrate in which the number of the chips belonging to the sameline is smaller, so that the number of the LED chips 11 constituting theseries circuit can be equalized. At this time, the LED chips 11 in thethree or more adjacent lines may be incorporated as the components ofthe series circuit.

Although the present invention has been described in terms of thepreferred embodiment, it will be appreciated that various modificationsand alternations might be made by those skilled in the art withoutdeparting from the spirit and scope of the invention. The inventionshould therefore be measured in terms of the claims which follow.

What is claimed is:
 1. A light-emitting device comprising: a ceramicsubstrate having a rectangular outer shape in a top view; a plurality ofLED chips positioned around a center of a primary surface of saidceramic substrate; a resin dam formed on the primary surface of saidceramic substrate and provided so as to surround a mounting area inwhich said plurality of LED chips are provided; a first electrode landand a second electrode land which are electrodes to be connected to apower supply and are electrically connected to said plurality of LEDchips, said first and second electrode lands being provided outside saidresin dam and near corners of the primary surface of the substrate, eachof said first and second electrode lands having a shape defined by firstand second sides along the sides of said ceramic substrate defining thecorresponding corner, third and fourth sides shorter than and opposingto the first and second sides, respectively, and a fifth side betweenthe third and fourth sides; and a resin layer provided attaching to aninner side of said resin dam and covering said plurality of LED chips.2. The light-emitting device of claim 1, wherein said first and secondelectrode lands are located on the corners diagonally opposite to eachother.
 3. The light-emitting device of claim 2, wherein said first andsecond electrode lands include silver.
 4. The light-emitting device ofclaim 2, further comprising: a first wire provided on said ceramicsubstrate and connected to said first electrode land, said first wireextending from said first electrode land to a portion under said resindam; and a second wire provided on said ceramic substrate and connectedto said second electrode land, said second wire extending from saidsecond electrode land to the other portion under said resin dam, whereinsaid plurality of LED chips are electrically connected to said first andsecond electrode lands via said first and second wire, respectively.